Power supply

Abstract

A power supply includes an output terminal, a power converting unit, an internal circuit and an internal power supplying unit. The output terminal outputs a first power. The power converting unit is coupled with the output terminal and receives the first power. The power converting unit converts the first power into a second power. The internal circuit is coupled with the power converting unit and receives the second power. The internal power supplying unit is coupled with the internal circuit.

What is claimed is: 
     
         1 . A power supply comprising:
 an output terminal outputting a first power;   a power converting unit coupled with the output terminal for receiving the first power, wherein the power converting unit converts the first power into a second power;   an internal circuit coupled with the power converting unit for receiving the second power; and   an internal power supplying unit coupled with the internal circuit.   
     
     
         2 . The power supply according to  claim 1 , wherein the power supply is applied to an external load and the external load is in non-loading or low loading status. 
     
     
         3 . The power supply according to  claim 1 , wherein the power converting unit comprises a clamping circuit. 
     
     
         4 . The power supply according to  claim 3 , wherein the clamping circuit comprises a zener diode and a resistor connected in series. 
     
     
         5 . The power supply according to  claim 1 , wherein the internal circuit comprises at least an electronic device. 
     
     
         6 . The power supply according to  claim 5 , wherein the electronic device is a chip, a resistor, a capacitor, a transistor or their combinations. 
     
     
         7 . The power supply according to  claim 1 , wherein the internal power supplying unit outputs a third power to the internal circuit. 
     
     
         8 . The power supply according to  claim 7 , wherein the internal circuit comprises a controller for controlling the internal circuit to receive the second power outputted by the power converting unit or the third power outputted by the internal power supplying unit. 
     
     
         9 . A power supply comprising:
 a first output terminal outputting a first power;   a power converting unit coupled with the first output terminal and receiving the first power, wherein the power converting unit converts the first power into a second power;   a second output terminal coupled with the power converting unit and outputting the second power;   an internal circuit; and   an internal power supplying unit coupled with the internal circuit.   
     
     
         10 . The power supply according to  claim 9 , wherein the power supply is applied to an external load and the external load is in non-loading or low loading status. 
     
     
         11 . The power supply according to  claim 9 , wherein the power converting unit comprises a clamping circuit. 
     
     
         12 . The power supply according to  claim 11 , wherein the clamping circuit comprises a zener diode and a resistor connected in series. 
     
     
         13 . The power supply according to  claim 9 , further comprising:
 a control unit coupled with the power converting unit and the internal circuit.   
     
     
         14 . The power supply according to  claim 13 , wherein the control unit is a transistor or a switch. 
     
     
         15 . The power supply according to  claim 9 , wherein the internal circuit comprises at least an electronic device. 
     
     
         16 . The power supply according to  claim 15 , wherein the electronic device is a chip, a resistor, a capacitor, a transistor or their combinations. 
     
     
         17 . The power supply according to  claim 9 , wherein the internal power supplying unit outputs a third power to the internal circuit. 
     
     
         18 . The power supply according to  claim 17 , wherein the internal circuit comprises a controller for controlling the internal circuit to receive the second power outputted by the power converting unit or the third power outputted by the internal power supplying unit.